This invention relates to attractant compositions for synanthropic flies. Throughout history, synanthropic flies have distinguished themselves as persistent pests and health threats to both man and animals. Studies have been made documenting flies as carriers of disease. As a result, substantial time and effort has been expended to develop pesticides and insecticides which can be broadcast throughout entire areas either in the form of sprays or as solids in order to shorten the life of these insects. Recent studies have shown that the widespread use of insecticides in an indiscriminate manner has far greater ramifications than originally thought when the impact on man and his environment is examined. Consequently, there has been increasing interest generated in localized trapping of pests by the use of attractants which draw them to a central location containing the specific agents for eliminating them.
Synanthropic flies are prolific breeders and experiments have been conducted directed to the control of the breeding process to reduce the fly population. Also, studies directed to the identification and synthesis of a sex attractant pheromone of the house fly, Musca domestica, were conducted successfully several years ago and resulted in the isolation of the pheromone cis-9-tricosene. This sex pheromone has received wide acceptance as an attractant for house flies. The synthesis of such pheromones is relatively expensive, rendering their widespread application costly. As a result, cis-9-tricosene is normally used in combination with low-cost carriers, thereby reducing the overall costs.
Furthermore, because flies are known to breed in environments promoting fermentation and microbial degradation, some attempts have been made to create fly attractants that have centered about the use of putrified or fermented materials (U.S. Pat. No. 3,846,557) or chemical isolates thereof (U.S. Pat. No. 3,996,349) to attract flies to a central location. The compounds indole and skatole are known as feeding attractants for flies and have been used in combination with nitrogenous materials such as trimethylamine and ammonia (U.S. Pat. No. 3,996,349). These compositions can be prepared in an aqueous mixture which is used as a liquid to attract flies, or can be employed with solid carriers such as sugar, clay or other inert porous materials.
While pheromones used as sex attractants and nitrogenous matter used as feeding attractants have been developed and used in connection with both liquid and solid mixtures, long-term fly control should place greater emphasis on the attraction of the female fly. The common house fly is a polygamous creature and a proportionately small number of male flies are all that is needed to fertilize a larger female population. Thus, attracting a male fly to a trap or insecticide has an immediate effect on the existing fly population, but essentially no impact on the size of the succeeding fly generation. It is common place for a female house fly to have the reproductive capacity to produce a thousand or more offspring. The killing of a female fly removes her remaining fecundity from the next generation. Thus, any control measure that operates to remove proportionately more females than males is vastly superior in terms of its impact on the next fly generation.
Accordingly, it is an object of the present invention to provide an attractant for synanthropic flies which utilizes a number of constituents which might each serve to some degree as an attractant, but interact in a manner to provide greater than expected efficacy. A further important feature of the invention is the provision of a fly attractant exhibiting a greater attractive effect upon the female fly than the male fly. Also, the invention provides an attractant having the ability to be marketed in a concentrated form, a dry diluted form, or in a liquid form. Further, the present novel attractant utilizes a plurality of individual attractants interacting to exhibit an enhanced attractive effect for reducing the cost per attracted fly.